Computer history

 

Digital computers

In contrast to analog computers, digital computers represent information in discrete form, generally as sequences of 0s and 1s (binary digits, orbits). the fashionable era of digital computers began within the late 1930s and early 1940s within us, Britain, and Germany. Their programs were stored on punched paper or cards, and that they had limited internal data storage. 

Mainframe computer

International Business Machines Corporation (IBM), andother companies made large, expensive computers of accelerating power.  

These computers came to be called mainframes, though the term didn't become common until smaller computers were built. fast components, and powerful computational abilities. They were highly reliable, and, because they often served vital needs in a corporation, they were sometimes designed with redundant components that permit them to survive partial failures. Because they were complex systems, they were operated by a staff of systems programmers, who alone had access to the pc. 

Central computing resources of a corporation, which can typically have hundreds or thousands of private computers. they permit hundreds or thousands of users to run programs simultaneously. due to their current roles, these computers are now called servers instead of mainframes